I've read tons of good things about the SMD Lunar Duo. An alternative which is nominally lighter and larger inside is the Lightheart Gear Duo. The Lunar Duo has a vent at the top to help control condensation--which is apparently an issue for both of these tents. Most of the reviews of the LHG Duo are positive except this one:

http://www.trailspace.com/gear/lightheart-gear/duo/

How serious are the condensation and rain-water sag issues for these tents?

I have the Lunar Duo and love it. It does tend to sag a bit if it rains but it's never been an issue for me. I make my trekking poles about 4 inches longer than they need to be when I initially set up the tent. I then put the tent up with the poles at an angle (leaning in towards the tent). If it rains and the tent begins to sag a little I simply unzip each door and pull the trekking pole in a bit and the tent is instantly taut again. I've only ever had to do it once per rainstorm.

Condensation, especially in rainy conditions, is a bit of a problem. I tend to pitch the Lunar Duo as high as I'm able to maximize the ventilation coming through. It hasn't prevented condensation, but it helps.

Kevin--thanks for the tip. That's a great idea. BTW: Do you recall how long you need to make the poles? I have a pair of helinox 135cm poles. I hope they're long enough.

Jacob--yes, I did see your review. Would you know whether the condensation and sag problems are more prevalent in the Lightheart or the SMD? I'll need a tent big enough to accommodate two large neoair mattresses (2*25in = 50in wide), so I think the DR is out (although I seem to remember they're being some way in which you can expand the width). I was attracted to the low weight of the Lightheart. I presume both tents should be used with their tyvek ground sheets. So, I'm tempted to go with the Lightheart, but I'm wondering whether the absence of a vent up top makes the condensation issue worse. Also, is the link to negative review I found consistent at all with what you'd expect from the Lightheart?

Sorry - I don't know how long I make the poles...It varies with conditions:

- If it's rainy & windy I'm likely to pitch the tent a little closer to the ground and count on the wind to enhance ventilation

- If it's just rainy but little wind (or little chance of rain) I'll be pitching it as high as possible to maximize ventilation

I use adjustable trekking poles so it's not a big deal to tweak the height of the Lunar Duo according to conditions. That flexibility is one of the things I really like about using trekking poles rather than fixed-length poles sold by SMD.

I have the Duo and I love it. Sagging in the rain is just something that all tents made with silnylon do. I can say for sure that I'd rather be in this than my Tarptent in the rain. The silnylon is much more resistant to rain misting through. Silnylon tents do require re-staking in the rain. This tent has a fabulous bathtub floor. That said, if I had tons of money, I'd love to get a fully double walled tent for using in the rain. But, I feel that this tent does fine for the occasional sprinkle. People who are willing to use silnylon tents in the rain have to expect that they will need to restake in the rain, and or adjust tent height, and keep a towel handy for mopping up condensation. Everything has pros and cons.

I also use the Lunar Duo and cannot stress enough how big it is inside. I will take it along with my two daughters (7 and 11 yo) and it fits the three of us comfortably if a bit cozy. The large panels can be a bit sail like in the wind requiring an additional two stakes if it is going to be windy. It would be way overkill for one person.

I have had occasional condensation and a bit of misting during an all-night heavy rain.

I slept in the LH Duo for one night; it WAS a very wet night (i.e. dew, but no rain) as other campers in the area agreed, but condensation was definitely a problem. My impression of the tent was that it was less breezy than, say, our Tarptent Cloudburst, so it probably does have more condensation than a breezier tent. I sold the tent not because of condensation issues but because my partner knocked the (interior) trekking pole on his side out of kilter a few times in his sleep, so the tent wasn't going to be for us. I suspect on most California nights, the tent would not have had such dire condensation, but still perhaps more than some designs. The SMD has more headroom IIRC, so condensation might not be so much "in your face" literally and figuratively.

Cary's comment is right on - sagging is a feature of silnylon. The more of it, the more stretch. The SMD utilizes a lot of material.

Rafi, regarding that review, if that was their experience then it is what it is, as the saying goes. However, from reading that review I notice a few things. They dinged the tent for not having a rain fly and being a single walled tent... well all I can say to that is duh! I get the feeling this person didn't research of understand the differences between single wall and double wall shelters and their expectations were not realistic. I don't find the tent difficult to setup, nor would I have a problem setting it up in the rain (why would this make setting up any tent more difficult??).

Personally, I have not used the LH Duo that much. It doesn't vent quite as well as the SMD in my experience, which can be a little breezy. It is a roomy tent, but the SMD is king when it comes to room for two... it also has a big footprint, which can sometimes be a challenge to plop down in the woods.

Judy is putting peak vents into the SoLong 6 (nice tent, by the way), so I have to wonder if the Duo will (or has been) updated to include them too? I think Judy is on vacation (or possibly traveling for business) but I'll see if I can get an answer on that, I'm curious now.

edit: Talked to Judy briefly, the current design of the Duo does not have peak vents. It sounds like she has plans to implement the same sort of vents that the SoLong has, but didn't give me specifics on when that would happen. Judy is generally very easy to get in touch with. If you have any questions I'm sure she would happily answer them.

It sounds like the LH Duo with venting could be the way to go. I have a Lightheart solo and have dealt with Judy in the past (she's great). I suppose I'd have to wait until they actually start producing the duo with venting -- unless they can do a custom design...

Not sure how you are measuring, but given how the side walls are arranged between the two tents, I cannot imagine that the Lightheart duo is "larger inside" than the SMD Lunar Duo. The Lightheart looks like it might have a little more interior volume than the Tarptent Double Rainbow, which we owned for a couple of years, but the SMD Lunar Duo has long side walls that are vertical - not sloped inward. Judging from the photos at the hikeitlikeit site, the SMD Duo is just immensely larger -- which squares with our own experience with this tent.

Perhaps the floor size of the Lightheart is larger, I'm not sure. But that's not the whole story by any means. We've had the Lunar Duo for several years, and have never seen a two person lightweight tent with that sort of usable interior volume.

Good luck with the decision -- there are many excellent choices these days.